The Morphology, Effects of Temperature and Photoperiod on Pseudopupal Diapause and Low Temperature Storage of Epicauta impressicornis (Coleoptera: Meloidae)

Abstract

The gross morphology of each phase of the hypermetamorphic development of Epicauta impressicornis Pic (Coleoptera: Meloidae) was observed. The effects of temperature and photoperiod on pseudopupal (5th instar larva) diapause and low temperature storage on eggs and pseudopupae were determined. Low temperatures had a dominant effect on diapause incidence, regardless of the photoperiod. Pseudopupae stored at temperatures lower than 18 °C entered diapause, but completed their development without entering diapause at 21, 24, and 27 °C. The critical temperature for inducing diapause was between 16 °C and 16.5 °C, regardless of the photoperiod. The viability of low temperature storage of eggs and pseudopupae decreased with prolongation of storage time. The optimal storage condition for both eggs and pseudopupae was 4 °C for 30 days. Our results will provide a theoretical basis for additional studies on the biological characteristics of E. impressicornis and will also function as a prerequisite basic reference for the artificial large-scale rearing of E. impressicornis.